The cultivated olive is a broad-leafed evergreen tree having the ability to survive highly unfavourable semi-arid conditions and capable of living to more than a thousand years old. The tree can become large and spreading although different cultivars vary in their growth habit and vigour. Branches are numerous and their bending downwards and subsequent reiteration growth gives the tree a thick brushy appearance.
Young wood is tough yet flexible, whereas older wood becomes very heard and strong. The trunks of older trees become ridged as a result of differential cambial activity, and these ridges sometimes spread outward at the base forming a broad corrugated buttress on which swellings occur.
The root system is generally shallow and spreading although root depth is influenced by the nature of the soil. About 80% of the roots occur in top 60cm of soil.
The leaves are arranged alternatively opposite on the shoot, usually coloured silvery grey on the underside and dark green on the upper side. The leaves adhere to the tree for two to three years then these older leaves turn yellow and drop, usually in spring.
Olive Production in South Africa. (A Handbook for Olive Growers), by Carlo Costa.